If offloading features are not negotiated, parsing the virtio header
is not needed.
Micro-benchmark with testpmd shows that the gain is +4% with indirect
descriptors, +1% when using direct descriptors.
Signed-off-by: Maxime Coquelin <maxime.coquelin at redhat.com>
---
Changes since v2:
=================
- Simplify code by translating first desc address
unconditionnaly (Yuanhan)
- Instead of checking features again, check whether
hdr has been assign to call offload function.
Changes since v1:
=================
- Rebased
- Fix early out check in vhost_dequeue_offload
lib/librte_vhost/virtio_net.c | 33 +++++++++++++++++++++++++--------
1 file changed, 25 insertions(+), 8 deletions(-)
diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index 812e5d3..15ef0b0 100644
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -555,6 +555,18 @@ rte_vhost_enqueue_burst(int vid, uint16_t queue_id,
return virtio_dev_rx(dev, queue_id, pkts, count);
}
+static inline bool
+virtio_net_with_host_offload(struct virtio_net *dev)
+{
+ if (dev->features &
+ (VIRTIO_NET_F_CSUM | VIRTIO_NET_F_HOST_ECN |
+ VIRTIO_NET_F_HOST_TSO4 | VIRTIO_NET_F_HOST_TSO6 |
+ VIRTIO_NET_F_HOST_UFO))
+ return true;
+
+ return false;
+}
+
static void
parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr)
{
@@ -607,6 +619,9 @@ vhost_dequeue_offload(struct virtio_net_hdr *hdr, struct
rte_mbuf *m)
void *l4_hdr = NULL;
struct tcp_hdr *tcp_hdr = NULL;
+ if (hdr->flags == 0 && hdr->gso_type == VIRTIO_NET_HDR_GSO_NONE)
+ return;
+
parse_ethernet(m, &l4_proto, &l4_hdr);
if (hdr->flags == VIRTIO_NET_HDR_F_NEEDS_CSUM) {
if (hdr->csum_start == (m->l2_len + m->l3_len)) {
@@ -702,7 +717,7 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vring_desc
*descs,
uint32_t mbuf_avail, mbuf_offset;
uint32_t cpy_len;
struct rte_mbuf *cur = m, *prev = m;
- struct virtio_net_hdr *hdr;
+ struct virtio_net_hdr *hdr = NULL;
/* A counter to avoid desc dead loop chain */
uint32_t nr_desc = 1;
@@ -715,8 +730,10 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct
vring_desc *descs,
if (unlikely(!desc_addr))
return -1;
- hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr);
- rte_prefetch0(hdr);
+ if (virtio_net_with_host_offload(dev)) {
+ hdr = (struct virtio_net_hdr *)((uintptr_t)desc_addr);
+ rte_prefetch0(hdr);
+ }
/*
* A virtio driver normally uses at least 2 desc buffers
@@ -733,18 +750,18 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct
vring_desc *descs,
if (unlikely(!desc_addr))
return -1;
- rte_prefetch0((void *)(uintptr_t)desc_addr);
-
desc_offset = 0;
desc_avail = desc->len;
nr_desc += 1;
-
- PRINT_PACKET(dev, (uintptr_t)desc_addr, desc->len, 0);
} else {
desc_avail = desc->len - dev->vhost_hlen;
desc_offset = dev->vhost_hlen;
}
+ rte_prefetch0((void *)(uintptr_t)(desc_addr + desc_offset));
+
+ PRINT_PACKET(dev, (uintptr_t)(desc_addr + desc_offset), desc_avail, 0);
+
mbuf_offset = 0;
mbuf_avail = m->buf_len - RTE_PKTMBUF_HEADROOM;
while (1) {
@@ -831,7 +848,7 @@ copy_desc_to_mbuf(struct virtio_net *dev, struct vring_desc
*descs,
prev->data_len = mbuf_offset;
m->pkt_len += mbuf_offset;
- if (hdr->flags != 0 || hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE)
+ if (hdr)
vhost_dequeue_offload(hdr, m);
return 0;
--
2.7.4
